On Fri, May 16, 2014 at 2:01 AM, Marcus Leech <mle...@ripnet.com> wrote:
> Gnu Radio is a streaming architecture. Sample-rate is actually > almost-entirely meaningless within the flowgraph, and only really > has meaning "at the edges" when interfacing to the real world. The only > exception is the throttle block, and even it doesn't > produce *precise* sample-rates. > A too-low value of sample-rate (samp_rate) could be hazardous. For example, in Jason's flowgraph attached in his previous email, the settings of the Signal Source block are: - Sample Rate = 100 - Frequency = 50 - Signal Type = Saw Tooth In this case the output from this block is just a repeating of two float numbers:- 0.5, 0.0, 0.5, 0.0, 0.5, 0.0, 0.5, 0.0, 0.5, .... If the Sample Rate is reduced to 50, then the output becomes a constant value:- 0.5, 0.5, 0.5, 0.5, ... (this is worse). If "Saw Tooth" is the signal pattern that he really wants out from this Signal Source block, then he needs to set the sample-rate to a high-enough value, for example, samp_rate=1000. With this value the Signal Source block will produce output which looks more like Saw Tooth:- 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 0.00, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 0.00, 0.05, 0.10, 0.15, ................. Hence, the value of samp_rate does make a significance in the flowgraph.
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